Conventional LED controllers are typically powered by direct current. Because of this limitation, their applications are limited as they would be battery powered or would require conversion of power produced in other forms to direct current. To work with an alternating current power source, conventional LED controllers would require a power adaptor as a transformer, which increases the cost and limits the usage of LEDs. Therefore, there is a need for an improved LED controller that addresses the limitations of the conventional LED controllers.
LED drivers implemented with integrated circuits would have to deal with inherent variations in manufacturing processes, which can affect the accuracy of the currents used to drive the LEDs. A conventional approach is to use an adjustable current setting resistor external to the LED driver integrated circuit for adjusting the current during the manufacturing of the printed circuit board. There are a few drawbacks with this conventional approach. First, this approach adds an additional component to the printed circuit board, which increases the size and thus the cost of the printed circuit board. Second, this approach requires the adjustable current setting resistor to be fine-tuned during the process of manufacturing of the printed circuit board, which increases the manufacturing cost of such conventional LED drivers. Thus, there is a need for methods and circuits that can address such issues of the conventional LED drivers.